Early detection of antibodies against various structural proteins of the SARS-associated coronavirus in SARS patients

Abstract

Severe acute respiratory syndrome (SARS), a new disease with symptoms similar to those of atypical pneumonia, raised a global alert in March 2003. Because of its relatively high transmissibility and mortality upon infection, probable SARS patients were quarantined and treated with special and intensive care. Therefore, instant and accurate laboratory confirmation of SARS-associated coronavirus (SARS-CoV) infection has become a worldwide interest. For this need, we purified recombinant proteins including the nucleocapsid (N), envelope (E), membrane (M), and truncated forms of the spike protein (S1-S7) of SARS-CoV in Escherichia coli. The six proteins N, E, M, S2, S5, and S6 were used for Western blotting (WB) to detect various immunoglobulin classes in 90 serum samples from 54 probable SARS patients. The results indicated that N was recognized in most of the sera. In some cases, S6 could be recognized as early as 2 or 3 days after illness onset, while S5 was recognized at a later stage. Furthermore, the result of recombinant-protein-based WB showed a 90% agreement with that of the whole-virus-based immunofluorescence assay. Combining WB with existing RT-PCR, the laboratory confirmation for SARS-CoV infection was greatly enhanced by 24.1%, from 48.1% (RT-PCR alone) to 72.2%. Finally, our results show that IgA antibodies against SARS-CoV can be detected within 1 week after illness onset in a few SARS patients.

Comparative Epidemiology of Human Infections with Middle East Respiratory Syndrome and Severe Acute Respiratory Syndrome Coronaviruses among Healthcare Personnel

“…Respiratory samples obtained from any reported suspected SARS cases were sent to the Center for Disease Control in Taiwan (Taiwan-CDC) for confirmation by RT-PCR or serology. The details of all the laboratory methods (molecular RT-PCR or serological tests) to confirm SARS-CoV were as previously described [ 11 ].…”

Evaluation of metal‐conjugated compounds as inhibitors of 3CL protease of SARS‐CoV

“…After electrophoresis, the proteins were transferred onto a Hybond‐C extra membrane using a semidry apparatus (Amersham Biosciences, Buckinghamshire, UK). The membranes were blocked with Blotto/Tween blocking buffer (5 mM Tris, pH 7.4, 77 mM NaCl, 0.05% Tween 20, 2.5% skimmed milk, and 0.001% antiform A) and then incubated with BALB/c anti‐rS268, which is an anti‐spike polyclonal antibody [17]. The membrane was then washed with blocking buffer and further incubated with goat anti‐mouse HRP‐conjugated secondary antibody.…”

The SARS-CoV-2 T-cell immunity is directed against the spike, membrane, and nucleocapsid protein and associated with COVID 19 severity

“…Besides the S-protein, also the N-and M-proteins were suggested as potential targets for diagnostic and prophylactic approaches 3,5 . In fact, B cell responses against the N-protein seemed to be the first to arise 4-8 days after symptom onset for the 2002/03 SARS-CoV infection 12,13 , which indicates that also N-reactive T cell response are prevalent during this timeframe. However, data on T cell responses towards the N-and M-proteins for the pandemic SARS-CoV-2 infection are currently not available.…”